Scientific Generics Limited

Andrew James White

Euan Morrison

Ross P Jones

Richard Alan Doyle

Peter Georg Laitenberger

Robin Michael Lee

Victoria Ann Clark

The present invention provides a position sensor which is suitable for use in a piston and cylinder assembly. The position sensor includes a movable field modifying member which is operable to vary the inductance of a sensor winding, whereby the position of the field modifying member relative to the sensor winding can be determined by monitoring the inductance of the sensor winding. The position sensor also includes a compensation winding which is arranged to have a common coupling with the field modifying member whereby a signal output from the compensation winding can be used to compensate for variations in the signal level output by the sensor winding caused by, for example, temperature variations of the system.

Position sensor

A linear position sensor is provided which employs phase quadrature sensor windings, an excitation winding and a resonator. When an excitation current is applied to the excitation winding, it causes the resonator to resonate which in turn induces signals in the sensor windings. The sensor windings are spatially arranged so that the electromagnetic coupling between them and the resonator varies with the position of the resonator. The excitation windings, phase quadrature windings and resonant circuit are arranged so that the magnetic fields involved in the operation of the position sensor are substantially parallel to each other and the direction of movement of the resonator. Consequently, the effect of rotation of the resonator or lateral movement of it relative to the excitation and phase quadrature windings is alleviated.

Position encoder

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Harston, United Kingdom

Andrew James White